1. Field of the Invention
The present invention relates to a die bonder.
2. Description of the Related Art
A die bonder is an apparatus which bonds a die (silicon wafer chip integrating electric circuits) to a lead frame, substrate or the like (hereinafter, referred to as “substrate”) using solder, gold plate or resin as a bonding material. An engineering plastic is used as a die bond material (paste, film) for bonding the die and the substrate together. After positioning, the die is bonded to the lead frame or the like. A method of implementing bonding using a resin as the bonding material is now predominant.
In semiconductor die bonding, solder or resin paste for die bonding (Ag epoxy and Ag polyimide) is used as an adhesive for fixing a semiconductor chip (IC, LSI) to the lead frame, ceramic case, substrate or the like.
The adhesive for bonding the die to the substrate is applied by a syringe which is vertically movable and ejects a paste adhesive. Specifically, the syringe enclosing therein the paste adhesive applies a predetermined amount of adhesive to a predetermined place on the substrate.
In this regard, the syringe containing therein the paste adhesive and a pattern on the lead frame need be checked by capturing an image thereof with a recognition camera before a bonding operation is carried out. It is therefore a conventional practice to move the recognition camera to an imaging position for acquiring the image and to detect a proper bonding position before carrying out the bonding operation. After bonding, the recognition camera is moved again to the imaging position to acquire an image for determination as to whether the paste adhesive is properly applied or not.
In this manner, the conventional die bonder causes the recognition camera to make two runs to the imaging position for image acquisition each time the paste adhesive is applied to the lead frame. These are quite wasteful steps. Namely, the conventional die bonder involves an inefficient movement to lower throughput per unit time.
In addition, a clear image free from the moiré phenomenon is necessary for making an exact determination of an application position of the paste adhesive and an amount of applied paste adhesive, to thereby prevent product failure.
However, the above JP-A No.2001-127080 and JP-A No.2004-288715 do not give due consideration to the increase in the throughput of an adhesive application job although a camera for image recognition and an illumination element are provided.